1. Field of the Invention
The invention relates to a method for producing patterned layers on substrates, in particular for producing patterned layers with a vitreous structure of surfaces of substrates.
2. Description of Related Art
To manufacture in particular integrated semiconductor components, optoelectronic components or other sensor or emitter components, it may be necessary or advantageous to produce precisely patterned passivation layers. For example, it may be necessary to introduce openings into an encapsulation at some positions in order to allow electrical contacts to be made with the packaged part. Glass is highly regarded and used for a wide range of applications, inter alia on account of its excellent passivation properties. The permeability to gas molecules from air is, by way of example, lower by orders of magnitude than that of plastics, which are otherwise used for the packaging and encapsulation of, for example, semiconductor components, and consequently a material with a vitreous structure, such as in particular a glass, may have favorable effects on the service life of the components. Furthermore, glasses also offer excellent protection against water, water vapor and in particular also against aggressive substances, such as acids and bases.
However, accurate processing of glass layers presents problems. For example, it is known to use photopatternable glasses, such as for example FOTURAN. However, glasses of this type are extremely expensive. Furthermore, it is possible to wet-chemically or dry-chemically etch glasses. However, particularly in the case of glasses, it is only possible to achieve low etching rates, and consequently a method of this type is also slow and accordingly too expensive for mass production. Moreover, the subsequent etching may also damage or destroy the encapsulated part. Accurate patterns can also be produced on glasses by laser machining, but this technique too is very slow and too expensive for mass production. Furthermore, there are various known mechanical treatment processes, but generally these do not make it possible to achieve the level of accuracy which can be achieved with other methods.